Hollow fiber, artificial kidney with disposable dialyzing cartridge

ABSTRACT

A hollow-fiber, artificial kidney with a disposable dialyzing cartridge comprising a cylindrical body, a disposable dialyzing cartridge positioned during use within the body and having hollow dialyzing fibers therein, and flanges and other means to hold the assembled parts of the kidney in place.

United States Patent 1 1 3,698,560 Tapp et al. [4 1 Oct. 17, 1972 HOLLOWFIBER, ARTIFICIAL KIDNEY WITH DISPOSABLE DIALYZING CARTRIDGE lnventors:James S. Tapp, Decatur, Ala.;

George L. Beemsterboer; lval 0. Salyer, both of Dayton, Ohio The UnitedStates of America as represented by the Secretary of the Department ofHealth, Education and Welfare Filed: Dec. 28, 1970 Appl. No.: 101,719

Assignee:

[56] References Cited UNITED STATES PATENTS 3,373,876 3/1968 Stewart..2l0/32l 3,228,876 1/1966 Mahon ..2l0/22 3,442,002 5/1969 Geary, Jr. eta1. .....2l0/32l X Primary Examiner-Frank A. Spear, Jr. Attorney--L.Bruce Stevens, Jr. and Frank D. Shearin [57] ABSTRACT A hollow-fiber,artificial kidney with a disposable dialyzing cartridge comprising acylindrical body, a disposable dialyzing cartridge positioned during usewithin the body and having hollow dialyzing fibers therein, and flangesand other means to hold the assembled parts of the kidney in place.

6 Claims, 1 Drawing Figure PATENTEflncI 11 1912 INVENTORS, JAMfS 5. TAPP65086! L. BEEMSTFFBOFR BY B441. 0. JALYEI? HOLLOW FIBER, ARTIFICIALKIDNEY WITH DISPOSABLE DIALYZING CARTRIDGE CROSS-REFERENCE TO RELATEDAPPLICATIONS Copending applications, Ser. No. 102,092 and 102,132 ofeven date describes and claims non-thrombogenic hollow-fiberhemodialysis membranes which can be used as the hollow fibers for thedialyzing cartridge of the artificial kidney of this application.

BACKGROUND OF THE INVENTION The invention described herein was made inthe course of, or under, a contract with the Department of Health,Education, and Welfare.

1. Field of the Invention The invention relates to liquid purificationand separation, and especially to semi-permeable membranes and is usefulin the dialysis art and especially in the hemo-dialysis or artificialkidney art.

2. Description of the Prior Art Typical hollow-fiber, artificial kidneysof the prior art are those described in US. Pat. Nos. 3,373,876,3,422,008 and 3,455,460.

SUMMARY OF THE INVENTION A hollow-fiber, artificial kidney with adisposable dialyzing cartridge comprising a first elongated hollow bodyopen at both ends, having inlet and outlet ports near oppositeends ofsaid body, and a gasket located in the inner wall of said body betweenthe inlet and outlet ports to prevent dialyzing fluid from goingdirectly from inlet to outlet; a disposable dialyzing cartridgecomprising a second elongated hollow body, sized to be inserted andremoved from inside said first body, having one or more openings on theside near each end positioned to communicate with the inlet and outletports of said first body, and hollow dialyzing fibers.

running longitudinally inside said second body and potted with resininto a reduced internal opening near at end to prevent leakage ofdialyzing fluid around the fibers and out of either end; a gasket ateach end of said first and second bodies to prevent dialyzing fluid fromleaking into blood, a flange at each end of said bodies andmeans-joining said flanges to hold said bodies and the gaskets at eachend in place. Preferred shape for the bodies of the kidney arecylindrical and it is also preferred that the kidney include anecked-down longitudinal portion adjacent each end gasket to facilitateconnectingthe kidney for use.

BRIEF DESCRIPTION OF THE DRAWING The drawing is an exploded viewpartially in section of the artificial kidney of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawing,hollow cylindrical body 1 forms the outer shell of the kidney. Portions7 at either end of body 1 are of reduced external diameter toaccommodate flanges l5. Inlet port 2 communicates from outside body 1 tothe inside with circumferential channel 6 for the purpose of introducingdialyzing fluid to the disposable cartridge. Gasket 4, an O-ring, ispositioned in a circumferential channel in the inner surface of body 1for the purpose of preventing dialysis fluid from passing directly frominlet port 2 to outlet port 3 when the disposable cartridge is in place.Outlet port 3 is an opening similar to port 2 communicating with asimilar circumferential channel in the inner surface of body 1 and isfor the purpose of removing dialysis fluid.

Body 8 of the disposable cartridge is a hollow cylindrical body of thesame length as body 1. The internal diameter of body 8 is larger in thecentral portion than at each end to facilitate the potting ofhollow-fibers 11 into each end of body 8 providing a seal so thatdialysis fluid cannot leak out from inside through the ends tocontaminate blood being processed. Inlet openings 10 are positionedcircumferentially on body 8 communicating from outside to inside thebody and openings 10 are positioned to communicate with channel 6 ofbody 1 when the artificial kidney is assembled. Openings 9 are similarto openings 10, but are positioned near the other end of body 8 tocommunicate with outlet port 3 of body 1 when the kidney is assembled.Body 8 is beveled at each end with a bevel such as 12 to facilitate theinsertion of the disposable cartridge to body 1. Gaskets 13 positionedat each end of bodies 1 and 8 when assembled serve to prevent dialysisfluid from leaking from either end between the outside surface of body 8and the inside surface of body 1. Necked-down portions 14 positionedbetween gaskets l3 and flanges 15 serve for the purpose of connectingthe artificial kidney for use with tubing. Flanges 15, rods 16 threadedat each end, and nuts 17 serve to hold the assembled portions of theartificial kidney firmly in place and prevent leakage.

Hollow fibers useful in the artificial kidney of this invention aredescribed in our copending applications, Ser. No. 102,092 and 102,132 ofeven date. These fibers are prepared from quaternized membranes ofpolymers made from monomeric substances of which at least a sufficientamount of a vinylpyridine is included to provide membranes which onheparinization are non-thrombogenic and at least 50% is acrylonitrile,particularly polymers made from monomeric substances of which from 2percent to 10 percent by weight of the total monomer is a vinylpyridineand at least percent by weight is acrylonitrile. Both the quaternizedand the heparinized polymers are useful in artificial kidneys; however,if only the quaternized polymers are used, it is necessary to heparinizethe patient to prevent clotting of the blood being processed. Othertypes of hollow fibers can also be used in the artificial kidney of thisinvention such as those fibers described in US. Pat. No. 3,441,142;however, the preferred fibers are those described in our copendingapplication.

It is preferred that all parts of the artificial kidney which come incontact with blood be non-thrombogenic, otherwise the patients bloodneeds to be heparinized. One method of making materials nonthrombogenicis disclosed in our copending application regarding the fibers whereinheparin was used. Another method of making certain materialsnon-thrombogenic, particularly epoxy resins is disclosed in application,Ser. No. 39,858, filed May 20, 1970, wherein certain polyethyleneglycols, polypropylene glycols and the like are used.

The disposable cartridge shown in the FIGURE can be made out ofpolymethyl methacrylate and the blood does not come in contact with thismaterial. The blood being processed flows through the hollow fibers, andgaskets l3 and necked-down portions 14 serve to transport the blooddirectly from the hollow fibers without contacting the polymethylmethacrylate case of the disposable cartridge. Non-thrombogenicity isprovided by fabricating all the blood contacting surfaces, including theblood headers, seals and fiber potting materials, from anon-thrombogenic epoxy, i.e., l3 and 14 of the FIGURE and the materialsused to pot the fibers of the disposable cartridge are all made fromnon-thrombogenic epoxy. This can be either epoxy which has beenheparinized according to prior art methods or can be the epoxy ofcopending application, Ser. No. 39,858 filed May 20, 1970, or othernon-thrombogenic material. Body 1, inlet and outlet ports 2 and 3 andthe like can also be made from Nylon, polymethyl methacrylate, otherplastic or metal since they do not come in contact with blood. Theflanges 15 can suitably be stainless steel or other metals since theytoo do not come in contact with blood.

A prototype hollow fiber kidney of the invention has been designed andbuilt having approximately 2,000 fibers, each of 15 centimeter dialyzinglength, i.e., the length inside the disposable cartridge contacted bydialyzing fluid, and a total fiber length of 21.6 centimeters whichwould be the same length as the disposable cartridge and body 1 of theFIGURE. The fibers used were those described in our copendingapplications, Ser. No. l02,092 and 102,132 of even date, and each fiberhas an inside diameter of about 250-280 microns and a wall thickness ofabout 50 microns. An actual commercial production model of theartificial kidney might be appreciably larger depending on the dialyzingcharacteristics of fibers used and in any event would be sizedpreferably to dialyze completely a patient within about 6 hours.

After the fibers have been prepared in accordance with our copendingapplications, Ser. No. 102,092 and 102,132 of even date, they arenormally stored wet with water to avoid loss of dialyzing propertiesuntil ready for potting into a disposable cartridge.

Prior to potting the disposable cartridge is longer than the final 21.6inches and the fibers are also appreciably longer than the cartridge andextend out both ends of the cartridge. Considerable care is needed inpotting to protect the dialyzing area of the fibers from the epoxypotting compound during fabrication. The epoxy compounds used to pot thefibers and bond them to themselves and to the polymethyl methacrylatedisposable cartridge case was a non-thrombogenic heparinized semi-rigidepoxy polymer which is known in the art for use where blood is contactedwith epoxy. The fibers are potted into the disposable cartridge, pottingone end at a time. Prior to potting fibers the disposable cartridge ashas been stated is somewhat longer at both ends and the cartridgeoverall length longer than the final 21.6 centimeters. The disposablecartridge with the fibers extending through the cartridge and out bothends for an appreciable extra length is placed in an upright hollowcylinder closed at the bottom and filled with glycerin. The disposablecartridge containing the hollow fibers is lowered down into the glycerinuntil all the dialyzing area is covered by glycerin, and the cartridgeis suspended at this point in the glycerin. Then the liquid heparinizedepoxy is poured around the fibers and floats on top of the glycerin.Care is taken to attempt to displace all the air bubbles from around thefibers to obtain a non-leaking seal potting the fibers to each other andinside the disposable cartridge at the upper end to the disposablecartridge. The heparinized epoxy resin is allowed to cure over a periodof several days as necessary at room temperature to pot the fibers inplace. The disposable cartridge with the fibers therein and one endpotted is then turned upside down and the process repeated to pot thefibers into the other end. A portion of each end of the disposablecartridge is cutoff reducing the length of the disposable cartridge to21.6 centimeters being very careful in the cutting of the fibers portionnot to crush fiber ends closing them. Then the edges of each end of thedisposable cartridge are beveled as at 12. Obviously other pottingmethods can also be used.

The method of potting the hollow dialyzing fibers described above can becarried out with any potting resin and other fluids can be used ratherthan glycerine. It is necessary in this method that the resin be oflower density than the glycerine or equivalent fluid, so the resin willfloat on top of the glycerine and not penetrate appreciably down theoutside of the fibers in the dialyzing area. It is preferable that thepotting resin be immiscible or at least not more than partially misciblewith the glycerine or equivalent fluid for best potting resultsotherwise there may be some reduction in dialyzing area of the fibersdue to coating by resin.

Several artificial kidneys of the invention of similar design to thatdescribed immediately above have been tested, in vivo, testing on humanbeings. For example, one artificial kidney tested on a human being had1,850 fibers and each had a total length of 21.6 centimeters and adialyzing length of 15 centimeters. The inside diameter of a fiber wasabout 250 microns. The wall thickness was 60 microns. The total dialysisarea of the fibers was 0.22 sq. meters, the membrane resistance cm./min.X lO, the ultrafiltration rate 50 ml./min./m. and the transmembranepressure during testing was 280 mm. of Hg. During the testing on thepatient blood was flowed through the fibers and dialyzing fluid aroundthe outside of the fibers. In this testing the artificial kidneyperformed satisfactory in dialyzing the patients blood, removing theblood urea nitrogen therefrom in a manner similar to a regular kidney.

Although the invention has been described in terms of the specifiedembodiments which are set forth in considerable detail, it should beunderstood that this is by way of illustration only and that theinvention is not necessarily limited thereto, since alternativeembodiments and operating techniques will become apparent to thoseskilled in the art in view of the disclosure. Accordingly, modificationsare contemplated which can be made without departing from the spirit ofthe described invention.

What is claimed is:

l. A hollow-fiber, artificial kidney with a disposable dialyzingcartridge comprising a first elongated hollow body open at both ends,having inlet and outlet ports near opposite ends of said body, and agasket located in the inner wall of said body between the inlet andoutlet ports to prevent dialyzing fluid from going directly from inletto outlet; a disposable dialyzing cartridge comprising a secondelongated hollow body, sized to be inserted and removed from inside saidfirst body, having one or more openings on the side near each endpositioned to communicate with inlet and outlet ports of said firstbody, and hollow dialyzing fibers running longitudinally inside saidsecond body and potted with resin into a reduced internal opening ateach end to prevent leakage of dialyzing fluid around the fibers and outof either end; a gasket at each end of said first and second bodies toprevent dialyzing fluid from leaking into blood, a flange at each end ofsaid bodies, and means joining said flanges to hold said bodies and thegasket at each end in place.

2. An artificial kidney of claim 1 having a neckeddown longitudinalportion adjacent each end to facilitate connecting said kidney for use.

3. An artificial kidney of claim 1 wherein the hollowfibers arequaternized heparinized hollowfibers of a polymer made from monomericsubstances of which at least a sufficient amount of a vinylpyridine isincluded to provide membranes which on heparinization arenon-thrombo-genic and at least 50 percent is acrylonitrile, saidhollow-fiber having a urea permeability in the range of 0.005 to 0.075cm./min. and an ultrafiltration rate in the range of 3 to 300ml./min./m. at 25 mm.Hg. transmembrane pressure, and all portions ofsaid kidney which are in contact with blood are heparinized to preventclotting of blood.

4. A method for potting hollow dialyzing fibers into an elongated hollowbody comprising positioning said body having a reduced opening at eachend and hollow dialyzing fibers running longitudinally through said bodyand out each end, in an upright hollow body closed at the bottom andhaving glycerine therein, adjusting the level of said elongated body andfibers in the glycerine until the dialyzing area of the fibers iscovered by glycerine but the upper end of said elongated body withprotruding fibers extends above the glycerine, adding a potting resin oflower density than glycerine around the fibers inside the upper end ofsaid elongated body taking care to displace air bubbles to facilitateobtaining a non-leaking seal of the fibers to each other and to theelongated body, curing said resin to obtain the seal, and repeating thepotting operation described herein above at the other end of saidelongated body.

5. A disposable dialyzing cartridge usable in a hollow-fiber artificialkidney comprising of an elongated hollow body beveled at both ends andadapted to be inserted and removed from said artificial kidney, havingone or more openings on the side at each end positioned to communicatewith inlet and outlet dialyzing fluid ports of an artificial kidney, andhollow dialyzing fibers running longitudinally inside said body andpotted with resin into a reduced internal opening near each end toprevent leakage of dialyzing fluid around the fibers and out of eitherend.

6. The disposable dialyzing cartridge of claim 5 wherein said hollowdialyzing fibers are quaternized heparinized hollow-fibers of a polymermade from monomeric substances of which at least a sufficient amount ofa vinylpyridine is included to provide membranes which on heparinizationare non-t hrombongenre and at least 50 percent acrylonitrile, saidhollowfiber having a urea permeability in the range of 0.005 to 0.075cm/min. and an ultrafiltration rate in the range of 3 to 300 ml/min./mat 25 mm. Hg. transmembrane pressure.

1. A hollow-fiber, artificial kidney with a disposable dialyzingcartridge comprising a first elongated hollow body open at both ends,having inlet and outlet ports near opposite ends of said body, and agasket located in the inner wall of said body between the inlet andoutlet ports to prevent dialyzing fluid from going directly from inletto outlet; a disposable dialyzing cartridge comprising a secondelongated hollow body, sized to be inserted and removed from inside saidfirst body, having one or more openings on the side near each endpositioned to communicate with inlet and outlet ports of said firstbody, and hollow dialyzing fibers running longitudinally inside saidsecond body and potted with resin into a reduced internal opening ateach end to prevent leakage of dialyzing fluid around the fibers and outof either end; a gasket at each end of said first and second bodies toprevent dialyzing fluid from leaking into blood, a flange at each end ofsaid bodies, and means joining said flanges to hold said bodies and thegasket at each end in place.
 2. An artificial kidney of claim 1 having anecked-down longitudinal portion adjacent each end to facilitateconnecting said kidney for use.
 3. An artificial kidney of claim 1wherein the hollow-fibers are quaternized heparinized hollow-fibers of apolymer made from monomeric substances of which at least a sufficientamount of a vinylpyridine is included to provide membranes which onheparinization are non-thrombo-genic and at least 50 percent isacrylonitrile, said hollow-fiber having a urea permeability in the rangeof 0.005 to 0.075 cm./min. and an ultrafiltration rate in the range of 3to 300 ml./min./m.2 at 25 mm.Hg. transmembrane pressure, and allportions of said kidney which are in contact with blood are heparinizedto prevent clotting of blood.
 4. A method for potting hollow dialyzingfiBers into an elongated hollow body comprising positioning said bodyhaving a reduced opening at each end and hollow dialyzing fibers runninglongitudinally through said body and out each end, in an upright hollowbody closed at the bottom and having glycerine therein, adjusting thelevel of said elongated body and fibers in the glycerine until thedialyzing area of the fibers is covered by glycerine but the upper endof said elongated body with protruding fibers extends above theglycerine, adding a potting resin of lower density than glycerine aroundthe fibers inside the upper end of said elongated body taking care todisplace air bubbles to facilitate obtaining a non-leaking seal of thefibers to each other and to the elongated body, curing said resin toobtain the seal, and repeating the potting operation describedhereinabove at the other end of said elongated body.
 5. A disposabledialyzing cartridge usable in a hollow-fiber, artificial kidneycomprising of an elongated hollow body beveled at both ends and adaptedto be inserted and removed from said artificial kidney, having one ormore openings on the side at each end positioned to communicate withinlet and outlet dialyzing fluid ports of an artificial kidney, andhollow dialyzing fibers running longitudinally inside said body andpotted with resin into a reduced internal opening near each end toprevent leakage of dialyzing fluid around the fibers and out of eitherend.
 6. The disposable dialyzing cartridge of claim 5 wherein saidhollow dialyzing fibers are quaternized heparinized hollow-fibers of apolymer made from monomeric substances of which at least a sufficientamount of a vinylpyridine is included to provide membranes which onheparinization are non-thrombogenic and at least 50 percentacrylonitrile, said hollow-fiber having a urea permeability in the rangeof 0.005 to 0.075 cm/min. and an ultrafiltration rate in the range of 3to 300 ml/min./m2 at 25 mm. Hg. transmembrane pressure.